Football helmet maker Riddell says it intends to vigorously defend its products and its reputation against concussion-related lawsuits like one lawyers for late New England Patriots tight end Aaron Hernandez have filed in Massachusetts against it and the NFL.

Des Plaines, Illinois-based Riddell says it introduced helmets designed to mitigate concussion risks more than 15 years ago.

Hernandez's attorneys filed a federal lawsuit last month after Hernandez killed himself in prison and an autopsy revealed he had chronic traumatic encephalopathy, a brain disease found in people who've suffered repetitive brain trauma such as concussions.

The lawsuit was refiled Monday. It accuses the NFL of hiding the dangers of football and names Riddell. It seeks damages for Hernandez's daughter.